SA and ROS are involved in methyl salicylate-induced programmed cell death in Arabidopsis thaliana.

Programmed cell death (PCD) is a genetically encoded, active process that results in the death of individual cells, tissues, or whole organs, which plays an important role in the life cycles of plants and animals. Previous studies show that methyl salicylate (MeSA) is a defense signal molecular associated with systemic acquired resistance and hypersensitive reaction; however, whether MeSA can induce PCD in plant is still unknown. The morphological changes of Arabidopsis thaliana protoplasts exposed to MeSA were observed under fluorescence microscopy and transmission electron microscopy, and the induction of PCD was clearly distinguished by intense perinuclear chromatin margination, condensation of nuclear chromatin and DNA laddering after 3-h exposure of 100 μM MeSA.

Production of reactive oxygen species, impairment of photosynthetic function and dynamic changes in mitochondria are early events in cadmium-induced cell death in Arabidopsis thaliana.

Background Information: Cadmium (Cd) is a highly toxic heavy metal that causes changes in plant metabolism through inhibiting photosynthesis and respiration. The effects of Cd on the morphology and function of the chloroplast and mitochondria, as well as on the production and localization of ROS (reactive oxygen species), were studied at the single-cell level in Arabidopsis.

Results: The present study showed that the morphology of chloroplasts changed after Cd treatment, and the photochemical efficiency dramatically declined prior to obvious morphological distortion in the chloroplasts.